Ashland police Chief Terry Holderness said Thursday the divers were using metal detectors to probe the bottom of the one-acre pond on a rural property on the outskirts of the neighboring town of Talent.

"We're not at the end of this," he said of the investigation.

Over the past year, police have interviewed nearly 2,000 people and sent several swords, machetes and knives to the state police crime lab for analysis without finding the weapon used to kill 23-year-old David Grubb.

Holderness said that despite the recent tip and renewed searches, authorities do not have a solid suspect.

About 50 people, including police from neighboring cities and counties, joined in the searches that started Wednesday.

While six divers probed the irrigation pond, others using dogs and metal detectors poked through fields, blackberry patches, old barns and sheds, junk piles and a home on the 18-acre Talent property. An FBI serial killer specialist was on hand, Holderness said.

"Just because we are doing search warrants doesn't mean the people who own the houses are involved in the case," Holderness said. "It just means there might be some evidence in the case at those properties."

Holderness said they got the tip about a month ago, and in that time developed enough information to ask a judge for three search warrants. Police have previously executed six other warrants in the case without making an arrest.

In Ashland, half a dozen officers seized a vehicle and searched an apartment a few blocks from where Grubbs was killed. It's part of the family student housing complex for Southern Oregon University.

Leonard Parrish, the owner with his wife of the Talent property, told the Ashland Daily Tidings he had no idea what was going on with the search.

The newspaper also reported that a vehicle registered to a woman living at the Ashland apartment was at one time registered at the Talent address.

Grubbs grew up in Ashland. He played in his high school orchestra and worked at a local grocery store. He had been walking home on a bike path past a park and an elementary school at dusk on Nov. 19, 2011, when he was killed, authorities say. Two passersby found him lying on the ground with horrible wounds to his head and neck.

Police have said no one witnessed the attack, and have spent the past year largely in frustration.

If the tip leads to an arrest, it would qualify for the reward, which has grown to $21,000 with contributions from the city and individuals, Holderness said.